Calculator · Estimate · Illinois
Illinois maintenance calculator
Illinois sets maintenance by formula: 33⅓% of payer’s net − 25% of recipient’s, capped at 40% of combined. Enter your numbers to apply it step by step, with the citation for each step.[1]
Key facts: maintenance in Illinois
| How the law sets it | Formula: we calculate[1] |
|---|---|
| The formula | 33⅓% of payer’s net − 25% of recipient’s, capped at 40% of combined[1] |
| Law last checked | October 26, 2026 |
How Illinois’s formula works, step by step
Guideline maintenance after divorce under 750 ILCS 5/504(b-1). Each step shows the arithmetic on your numbers and the source it comes from.
To see the steps, enter your income and your spouse’s income.
From the official text
What Illinois law says about maintenance
Plain-English summaries of Illinois’s statute and court rules as of the date shown on each, with the quoted text. Not legal advice: laws change and courts apply them case by case.
When it applies
Combined gross income under $500,000
The guideline applies when the couple’s combined gross annual income is under $500,000 and the payer owes no support from a prior relationship.[1]
750 ILCS 5/504(b-1) · checked October 26, 2026
Show statute text
“If the combined gross annual income of the parties is less than $500,000 and the payor has no obligation to pay child support or maintenance or both from a prior relationship”
Formula
33⅓% of payer net − 25% of recipient net
Maintenance is 33⅓% of the payer’s net annual income minus 25% of the recipient’s net annual income.[1]
750 ILCS 5/504(b-1) · checked October 26, 2026
Show statute text
“shall be calculated by taking 33 1/3% of the payor's net annual income minus 25% of the payee's net annual income.”
Amount cap
Recipient ≤ 40% of combined net income
Maintenance plus the recipient’s own net income can’t exceed 40% of the couple’s combined net income.[1]
750 ILCS 5/504(b-1) · checked October 26, 2026
Show statute text
“The amount calculated as maintenance, however, when added to the net income of the payee, shall not result in the payee receiving an amount that is in excess of 40% of the combined net income of the parties.”
How long it lasts
Years married × 0.20 to 0.80
Length is the years married times a factor from .20 (under 5 years) to .80 (19 to 20 years); for 20 years or more, the court orders maintenance for the length of the marriage or indefinitely.[1]
750 ILCS 5/504(b-1) · checked October 26, 2026
Show statute text
“For a marriage of 20 or more years, the court, in its discretion, shall order maintenance for a period equal to the length of the marriage or for an indefinite term.”
Divorce in Illinois: waiting period, residency and property rules →
Questions about alimony in Illinois
Is there an alimony calculator for Illinois?
Yes. Illinois sets a guideline by formula (Guideline maintenance after divorce under 750 ILCS 5/504(b-1)), and the calculator above applies it step by step. It's an estimate: courts decide and can depart from the guideline. — 750 ILCS 5/504(b-1)[1]
How long does alimony last in Illinois?
Length is the years married times a factor from .20 (under 5 years) to .80 (19 to 20 years); for 20 years or more, the court orders maintenance for the length of the marriage or indefinitely. — 750 ILCS 5/504(b-1)[1]
Is there a limit on alimony in Illinois?
Maintenance plus the recipient’s own net income can’t exceed 40% of the couple’s combined net income. — 750 ILCS 5/504(b-1)[1]
States with an alimony formula
Not legal advice. MediationList is a directory of court-listed mediators, not a law firm, and doesn’t endorse any mediator. Estimates follow the official formula as published; courts decide, and can depart from it.
Sources
Illinois’s statute and court rules, read on the official site, with the date we checked each.
- 750 ILCS 5/504(b-1) (Illinois General Assembly) (as amended by P.A. 103-967, eff. Jan. 1, 2025)↩